src/login/logind-session.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2011 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <errno.h>
  21 #include <fcntl.h>
  22 #include <linux/kd.h>
  23 #include <linux/vt.h>
  24 #include <signal.h>
  25 #include <string.h>
  26 #include <sys/ioctl.h>
  27 #include <unistd.h>
  28
  29 #include "sd-messages.h"
  30
  31 #include "alloc-util.h"
  32 #include "audit-util.h"
  33 #include "bus-error.h"
  34 #include "bus-util.h"
  35 #include "escape.h"
  36 #include "extract-word.h"
  37 #include "fd-util.h"
  38 #include "fileio.h"
  39 #include "format-util.h"
  40 #include "io-util.h"
  41 #include "logind-session.h"
  42 #include "mkdir.h"
  43 #include "parse-util.h"
  44 #include "path-util.h"
  45 #include "string-table.h"
  46 #include "terminal-util.h"
  47 #include "user-util.h"
  48 #include "util.h"
  49
  50 #define RELEASE_USEC (20*USEC_PER_SEC)
  51
  52 static void session_remove_fifo(Session *s);
  53
  54 Session* session_new(Manager *m, const char *id) {
  55         Session *s;
  56
  57         assert(m);
  58         assert(id);
  59         assert(session_id_valid(id));
  60
  61         s = new0(Session, 1);
  62         if (!s)
  63                 return NULL;
  64
  65         s->state_file = strappend("/run/systemd/sessions/", id);
  66         if (!s->state_file)
  67                 return mfree(s);
  68
  69         s->devices = hashmap_new(&devt_hash_ops);
  70         if (!s->devices) {
  71                 free(s->state_file);
  72                 return mfree(s);
  73         }
  74
  75         s->id = basename(s->state_file);
  76
  77         if (hashmap_put(m->sessions, s->id, s) < 0) {
  78                 hashmap_free(s->devices);
  79                 free(s->state_file);
  80                 return mfree(s);
  81         }
  82
  83         s->manager = m;
  84         s->fifo_fd = -1;
  85         s->vtfd = -1;
  86
  87         return s;
  88 }
  89
  90 void session_free(Session *s) {
  91         SessionDevice *sd;
  92
  93         assert(s);
  94
  95         if (s->in_gc_queue)
  96                 LIST_REMOVE(gc_queue, s->manager->session_gc_queue, s);
  97
  98         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
  99
 100         session_remove_fifo(s);
 101
 102         session_drop_controller(s);
 103
 104         while ((sd = hashmap_first(s->devices)))
 105                 session_device_free(sd);
 106
 107         hashmap_free(s->devices);
 108
 109         if (s->user) {
 110                 LIST_REMOVE(sessions_by_user, s->user->sessions, s);
 111
 112                 if (s->user->display == s)
 113                         s->user->display = NULL;
 114         }
 115
 116         if (s->seat) {
 117                 if (s->seat->active == s)
 118                         s->seat->active = NULL;
 119                 if (s->seat->pending_switch == s)
 120                         s->seat->pending_switch = NULL;
 121
 122                 seat_evict_position(s->seat, s);
 123                 LIST_REMOVE(sessions_by_seat, s->seat->sessions, s);
 124         }
 125
 126         if (s->scope) {
 127                 hashmap_remove(s->manager->session_units, s->scope);
 128                 free(s->scope);
 129         }
 130
 131 #if 0 /// elogind does not support systemd scope_jobs
 132         free(s->scope_job);
 133 #endif // 0
 134
 135         sd_bus_message_unref(s->create_message);
 136
 137         free(s->tty);
 138         free(s->display);
 139         free(s->remote_host);
 140         free(s->remote_user);
 141         free(s->service);
 142         free(s->desktop);
 143
 144         hashmap_remove(s->manager->sessions, s->id);
 145
 146         free(s->state_file);
 147         free(s);
 148 }
 149
 150 void session_set_user(Session *s, User *u) {
 151         assert(s);
 152         assert(!s->user);
 153
 154         s->user = u;
 155         LIST_PREPEND(sessions_by_user, u->sessions, s);
 156 }
 157
 158 static void session_save_devices(Session *s, FILE *f) {
 159         SessionDevice *sd;
 160         Iterator i;
 161
 162         if (!hashmap_isempty(s->devices)) {
 163                 fprintf(f, "DEVICES=");
 164                 HASHMAP_FOREACH(sd, s->devices, i)
 165                         fprintf(f, "%u:%u ", major(sd->dev), minor(sd->dev));
 166                 fprintf(f, "\n");
 167         }
 168 }
 169
 170 int session_save(Session *s) {
 171         _cleanup_free_ char *temp_path = NULL;
 172         _cleanup_fclose_ FILE *f = NULL;
 173         int r = 0;
 174
 175         assert(s);
 176
 177         if (!s->user)
 178                 return -ESTALE;
 179
 180         if (!s->started)
 181                 return 0;
 182
 183         r = mkdir_safe_label("/run/systemd/sessions", 0755, 0, 0);
 184         if (r < 0)
 185                 goto fail;
 186
 187         r = fopen_temporary(s->state_file, &f, &temp_path);
 188         if (r < 0)
 189                 goto fail;
 190
 191         assert(s->user);
 192
 193         fchmod(fileno(f), 0644);
 194
 195         fprintf(f,
 196                 "# This is private data. Do not parse.\n"
 197                 "UID="UID_FMT"\n"
 198                 "USER=%s\n"
 199                 "ACTIVE=%i\n"
 200                 "STATE=%s\n"
 201                 "REMOTE=%i\n",
 202                 s->user->uid,
 203                 s->user->name,
 204                 session_is_active(s),
 205                 session_state_to_string(session_get_state(s)),
 206                 s->remote);
 207
 208         if (s->type >= 0)
 209                 fprintf(f, "TYPE=%s\n", session_type_to_string(s->type));
 210
 211         if (s->class >= 0)
 212                 fprintf(f, "CLASS=%s\n", session_class_to_string(s->class));
 213
 214         if (s->scope)
 215                 fprintf(f, "SCOPE=%s\n", s->scope);
 216 #if 0 /// elogind does not support systemd scope_jobs
 217         if (s->scope_job)
 218                 fprintf(f, "SCOPE_JOB=%s\n", s->scope_job);
 219 #endif // 0
 220
 221         if (s->fifo_path)
 222                 fprintf(f, "FIFO=%s\n", s->fifo_path);
 223
 224         if (s->seat)
 225                 fprintf(f, "SEAT=%s\n", s->seat->id);
 226
 227         if (s->tty)
 228                 fprintf(f, "TTY=%s\n", s->tty);
 229
 230         if (s->display)
 231                 fprintf(f, "DISPLAY=%s\n", s->display);
 232
 233         if (s->remote_host) {
 234                 _cleanup_free_ char *escaped;
 235
 236                 escaped = cescape(s->remote_host);
 237                 if (!escaped) {
 238                         r = -ENOMEM;
 239                         goto fail;
 240                 }
 241
 242                 fprintf(f, "REMOTE_HOST=%s\n", escaped);
 243         }
 244
 245         if (s->remote_user) {
 246                 _cleanup_free_ char *escaped;
 247
 248                 escaped = cescape(s->remote_user);
 249                 if (!escaped) {
 250                         r = -ENOMEM;
 251                         goto fail;
 252                 }
 253
 254                 fprintf(f, "REMOTE_USER=%s\n", escaped);
 255         }
 256
 257         if (s->service) {
 258                 _cleanup_free_ char *escaped;
 259
 260                 escaped = cescape(s->service);
 261                 if (!escaped) {
 262                         r = -ENOMEM;
 263                         goto fail;
 264                 }
 265
 266                 fprintf(f, "SERVICE=%s\n", escaped);
 267         }
 268
 269         if (s->desktop) {
 270                 _cleanup_free_ char *escaped;
 271
 272
 273                 escaped = cescape(s->desktop);
 274                 if (!escaped) {
 275                         r = -ENOMEM;
 276                         goto fail;
 277                 }
 278
 279                 fprintf(f, "DESKTOP=%s\n", escaped);
 280         }
 281
 282         if (s->seat && seat_has_vts(s->seat))
 283                 fprintf(f, "VTNR=%u\n", s->vtnr);
 284
 285         if (!s->vtnr)
 286                 fprintf(f, "POSITION=%u\n", s->position);
 287
 288         if (s->leader > 0)
 289                 fprintf(f, "LEADER="PID_FMT"\n", s->leader);
 290
 291         if (s->audit_id > 0)
 292                 fprintf(f, "AUDIT=%"PRIu32"\n", s->audit_id);
 293
 294         if (dual_timestamp_is_set(&s->timestamp))
 295                 fprintf(f,
 296                         "REALTIME="USEC_FMT"\n"
 297                         "MONOTONIC="USEC_FMT"\n",
 298                         s->timestamp.realtime,
 299                         s->timestamp.monotonic);
 300
 301         if (s->controller) {
 302                 fprintf(f, "CONTROLLER=%s\n", s->controller);
 303                 session_save_devices(s, f);
 304         }
 305
 306         r = fflush_and_check(f);
 307         if (r < 0)
 308                 goto fail;
 309
 310         if (rename(temp_path, s->state_file) < 0) {
 311                 r = -errno;
 312                 goto fail;
 313         }
 314
 315         return 0;
 316
 317 fail:
 318         (void) unlink(s->state_file);
 319
 320         if (temp_path)
 321                 (void) unlink(temp_path);
 322
 323         return log_error_errno(r, "Failed to save session data %s: %m", s->state_file);
 324 }
 325
 326 static int session_load_devices(Session *s, const char *devices) {
 327         const char *p;
 328         int r = 0;
 329
 330         assert(s);
 331
 332         for (p = devices;;) {
 333                 _cleanup_free_ char *word = NULL;
 334                 SessionDevice *sd;
 335                 dev_t dev;
 336                 int k;
 337
 338                 k = extract_first_word(&p, &word, NULL, 0);
 339                 if (k == 0)
 340                         break;
 341                 if (k < 0) {
 342                         r = k;
 343                         break;
 344                 }
 345
 346                 k = parse_dev(word, &dev);
 347                 if (k < 0) {
 348                         r = k;
 349                         continue;
 350                 }
 351
 352                 /* The file descriptors for loaded devices will be reattached later. */
 353                 k = session_device_new(s, dev, false, &sd);
 354                 if (k < 0)
 355                         r = k;
 356         }
 357
 358         if (r < 0)
 359                 log_error_errno(r, "Loading session devices for session %s failed: %m", s->id);
 360
 361         return r;
 362 }
 363
 364 int session_load(Session *s) {
 365         _cleanup_free_ char *remote = NULL,
 366                 *seat = NULL,
 367                 *vtnr = NULL,
 368                 *state = NULL,
 369                 *position = NULL,
 370                 *leader = NULL,
 371                 *type = NULL,
 372                 *class = NULL,
 373                 *uid = NULL,
 374                 *realtime = NULL,
 375                 *monotonic = NULL,
 376                 *controller = NULL,
 377                 *active = NULL,
 378                 *devices = NULL;
 379
 380         int k, r;
 381
 382         assert(s);
 383
 384         r = parse_env_file(s->state_file, NEWLINE,
 385                            "REMOTE",         &remote,
 386                            "SCOPE",          &s->scope,
 387 #if 0 /// elogind does not support systemd scope_jobs
 388                            "SCOPE_JOB",      &s->scope_job,
 389 #endif // 0
 390                            "FIFO",           &s->fifo_path,
 391                            "SEAT",           &seat,
 392                            "TTY",            &s->tty,
 393                            "DISPLAY",        &s->display,
 394                            "REMOTE_HOST",    &s->remote_host,
 395                            "REMOTE_USER",    &s->remote_user,
 396                            "SERVICE",        &s->service,
 397                            "DESKTOP",        &s->desktop,
 398                            "VTNR",           &vtnr,
 399                            "STATE",          &state,
 400                            "POSITION",       &position,
 401                            "LEADER",         &leader,
 402                            "TYPE",           &type,
 403                            "CLASS",          &class,
 404                            "UID",            &uid,
 405                            "REALTIME",       &realtime,
 406                            "MONOTONIC",      &monotonic,
 407                            "CONTROLLER",     &controller,
 408                            "ACTIVE",         &active,
 409                            "DEVICES",        &devices,
 410                            NULL);
 411
 412         if (r < 0)
 413                 return log_error_errno(r, "Failed to read %s: %m", s->state_file);
 414
 415         if (!s->user) {
 416                 uid_t u;
 417                 User *user;
 418
 419                 if (!uid) {
 420                         log_error("UID not specified for session %s", s->id);
 421                         return -ENOENT;
 422                 }
 423
 424                 r = parse_uid(uid, &u);
 425                 if (r < 0)  {
 426                         log_error("Failed to parse UID value %s for session %s.", uid, s->id);
 427                         return r;
 428                 }
 429
 430                 user = hashmap_get(s->manager->users, UID_TO_PTR(u));
 431                 if (!user) {
 432                         log_error("User of session %s not known.", s->id);
 433                         return -ENOENT;
 434                 }
 435
 436                 session_set_user(s, user);
 437         }
 438
 439         if (remote) {
 440                 k = parse_boolean(remote);
 441                 if (k >= 0)
 442                         s->remote = k;
 443         }
 444
 445         if (vtnr)
 446                 safe_atou(vtnr, &s->vtnr);
 447
 448         if (seat && !s->seat) {
 449                 Seat *o;
 450
 451                 o = hashmap_get(s->manager->seats, seat);
 452                 if (o)
 453                         r = seat_attach_session(o, s);
 454                 if (!o || r < 0)
 455                         log_error("Cannot attach session %s to seat %s", s->id, seat);
 456         }
 457
 458         if (!s->seat || !seat_has_vts(s->seat))
 459                 s->vtnr = 0;
 460
 461         if (position && s->seat) {
 462                 unsigned int npos;
 463
 464                 safe_atou(position, &npos);
 465                 seat_claim_position(s->seat, s, npos);
 466         }
 467
 468         if (leader) {
 469                 k = parse_pid(leader, &s->leader);
 470                 if (k >= 0)
 471                         audit_session_from_pid(s->leader, &s->audit_id);
 472         }
 473
 474         if (type) {
 475                 SessionType t;
 476
 477                 t = session_type_from_string(type);
 478                 if (t >= 0)
 479                         s->type = t;
 480         }
 481
 482         if (class) {
 483                 SessionClass c;
 484
 485                 c = session_class_from_string(class);
 486                 if (c >= 0)
 487                         s->class = c;
 488         }
 489
 490         if (state && streq(state, "closing"))
 491                 s->stopping = true;
 492
 493         if (s->fifo_path) {
 494                 int fd;
 495
 496                 /* If we open an unopened pipe for reading we will not
 497                    get an EOF. to trigger an EOF we hence open it for
 498                    writing, but close it right away which then will
 499                    trigger the EOF. This will happen immediately if no
 500                    other process has the FIFO open for writing, i. e.
 501                    when the session died before logind (re)started. */
 502
 503                 fd = session_create_fifo(s);
 504                 safe_close(fd);
 505         }
 506
 507         if (realtime)
 508                 timestamp_deserialize(realtime, &s->timestamp.realtime);
 509         if (monotonic)
 510                 timestamp_deserialize(monotonic, &s->timestamp.monotonic);
 511
 512         if (active) {
 513                 k = parse_boolean(active);
 514                 if (k >= 0)
 515                         s->was_active = k;
 516         }
 517
 518         if (controller) {
 519                 if (bus_name_has_owner(s->manager->bus, controller, NULL) > 0) {
 520                         session_set_controller(s, controller, false, false);
 521                         session_load_devices(s, devices);
 522                 } else
 523                         session_restore_vt(s);
 524         }
 525
 526         return r;
 527 }
 528
 529 int session_activate(Session *s) {
 530         unsigned int num_pending;
 531
 532         assert(s);
 533         assert(s->user);
 534
 535         if (!s->seat)
 536                 return -EOPNOTSUPP;
 537
 538         if (s->seat->active == s)
 539                 return 0;
 540
 541         /* on seats with VTs, we let VTs manage session-switching */
 542         if (seat_has_vts(s->seat)) {
 543                 if (!s->vtnr)
 544                         return -EOPNOTSUPP;
 545
 546                 return chvt(s->vtnr);
 547         }
 548
 549         /* On seats without VTs, we implement session-switching in logind. We
 550          * try to pause all session-devices and wait until the session
 551          * controller acknowledged them. Once all devices are asleep, we simply
 552          * switch the active session and be done.
 553          * We save the session we want to switch to in seat->pending_switch and
 554          * seat_complete_switch() will perform the final switch. */
 555
 556         s->seat->pending_switch = s;
 557
 558         /* if no devices are running, immediately perform the session switch */
 559         num_pending = session_device_try_pause_all(s);
 560         if (!num_pending)
 561                 seat_complete_switch(s->seat);
 562
 563         return 0;
 564 }
 565
 566 #if 0 /// UNNEEDED by elogind
 567 static int session_start_scope(Session *s) {
 568         int r;
 569
 570         assert(s);
 571         assert(s->user);
 572
 573         if (!s->scope) {
 574                 _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 575                 char *scope, *job = NULL;
 576                 const char *description;
 577
 578                 scope = strjoin("session-", s->id, ".scope");
 579                 if (!scope)
 580                         return log_oom();
 581
 582                 description = strjoina("Session ", s->id, " of user ", s->user->name);
 583
 584                 r = manager_start_scope(
 585                                 s->manager,
 586                                 scope,
 587                                 s->leader,
 588                                 s->user->slice,
 589                                 description,
 590                                 "systemd-logind.service",
 591                                 "systemd-user-sessions.service",
 592                                 (uint64_t) -1, /* disable TasksMax= for the scope, rely on the slice setting for it */
 593                                 &error,
 594                                 &job);
 595                 if (r < 0) {
 596                         log_error_errno(r, "Failed to start session scope %s: %s", scope, bus_error_message(&error, r));
 597                         free(scope);
 598                         return r;
 599                 } else {
 600                         s->scope = scope;
 601
 602                         free(s->scope_job);
 603                         s->scope_job = job;
 604                 }
 605         }
 606
 607         if (s->scope)
 608                 (void) hashmap_put(s->manager->session_units, s->scope, s);
 609
 610         return 0;
 611 }
 612 #else
 613 static int session_start_cgroup(Session *s) {
 614         int r;
 615
 616         assert(s);
 617         assert(s->user);
 618         assert(s->leader > 0);
 619
 620         /* First, create our own group */
 621         r = cg_create(SYSTEMD_CGROUP_CONTROLLER, s->id);
 622         if (r < 0)
 623                 return log_error_errno(r, "Failed to create cgroup %s: %m", s->id);
 624
 625         r = cg_attach(SYSTEMD_CGROUP_CONTROLLER, s->id, s->leader);
 626         if (r < 0)
 627                 log_warning_errno(r, "Failed to attach PID %d to cgroup %s: %m", s->leader, s->id);
 628
 629         return 0;
 630 }
 631 #endif // 0
 632
 633 int session_start(Session *s) {
 634         int r;
 635
 636         assert(s);
 637
 638         if (!s->user)
 639                 return -ESTALE;
 640
 641         if (s->started)
 642                 return 0;
 643
 644         r = user_start(s->user);
 645         if (r < 0)
 646                 return r;
 647
 648         /* Create cgroup */
 649 #if 0 /// elogind does its own session management
 650         r = session_start_scope(s);
 651 #else
 652         r = session_start_cgroup(s);
 653 #endif // 0
 654         if (r < 0)
 655                 return r;
 656
 657         log_struct(s->class == SESSION_BACKGROUND ? LOG_DEBUG : LOG_INFO,
 658                    "MESSAGE_ID=" SD_MESSAGE_SESSION_START_STR,
 659                    "SESSION_ID=%s", s->id,
 660                    "USER_ID=%s", s->user->name,
 661                    "LEADER="PID_FMT, s->leader,
 662                    LOG_MESSAGE("New session %s of user %s.", s->id, s->user->name),
 663                    NULL);
 664
 665         if (!dual_timestamp_is_set(&s->timestamp))
 666                 dual_timestamp_get(&s->timestamp);
 667
 668         if (s->seat)
 669                 seat_read_active_vt(s->seat);
 670
 671         s->started = true;
 672
 673         user_elect_display(s->user);
 674
 675         /* Save data */
 676         session_save(s);
 677         user_save(s->user);
 678         if (s->seat)
 679                 seat_save(s->seat);
 680
 681         /* Send signals */
 682         session_send_signal(s, true);
 683         user_send_changed(s->user, "Display", NULL);
 684         if (s->seat) {
 685                 if (s->seat->active == s)
 686                         seat_send_changed(s->seat, "ActiveSession", NULL);
 687         }
 688
 689         return 0;
 690 }
 691
 692 #if 0 /// UNNEEDED by elogind
 693 static int session_stop_scope(Session *s, bool force) {
 694         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 695         int r;
 696
 697         assert(s);
 698
 699         if (!s->scope)
 700                 return 0;
 701
 702         /* Let's always abandon the scope first. This tells systemd that we are not interested anymore, and everything
 703          * that is left in the scope is "left-over". Informing systemd about this has the benefit that it will log
 704          * when killing any processes left after this point. */
 705         r = manager_abandon_scope(s->manager, s->scope, &error);
 706         if (r < 0)
 707                 log_warning_errno(r, "Failed to abandon session scope, ignoring: %s", bus_error_message(&error, r));
 708
 709         /* Optionally, let's kill everything that's left now. */
 710         if (force || manager_shall_kill(s->manager, s->user->name)) {
 711                 char *job = NULL;
 712
 713                 r = manager_stop_unit(s->manager, s->scope, &error, &job);
 714                 if (r < 0)
 715                         return log_error_errno(r, "Failed to stop session scope: %s", bus_error_message(&error, r));
 716
 717                 free(s->scope_job);
 718                 s->scope_job = job;
 719         } else
 720                 s->scope_job = mfree(s->scope_job);
 721
 722         return 0;
 723 }
 724 #else
 725 static int session_stop_cgroup(Session *s, bool force) {
 726         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
 727         int r;
 728
 729         assert(s);
 730
 731         if (force || manager_shall_kill(s->manager, s->user->name)) {
 732                 r = session_kill(s, KILL_ALL, SIGTERM);
 733                 if (r < 0)
 734                         return r;
 735         }
 736
 737         return 0;
 738 }
 739 #endif // 0
 740
 741 int session_stop(Session *s, bool force) {
 742         int r;
 743
 744         assert(s);
 745
 746         if (!s->user)
 747                 return -ESTALE;
 748
 749         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 750
 751         if (s->seat)
 752                 seat_evict_position(s->seat, s);
 753
 754         /* We are going down, don't care about FIFOs anymore */
 755         session_remove_fifo(s);
 756
 757         /* Kill cgroup */
 758 #if 0 /// elogind does not start scopes, but sessions
 759         r = session_stop_scope(s, force);
 760 #else
 761         r = session_stop_cgroup(s, force);
 762 #endif // 0
 763
 764         s->stopping = true;
 765
 766         user_elect_display(s->user);
 767
 768         session_save(s);
 769         user_save(s->user);
 770
 771 #if 1 /// elogind must queue this session again
 772         session_add_to_gc_queue(s);
 773 #endif // 1
 774
 775         return r;
 776 }
 777
 778 int session_finalize(Session *s) {
 779         SessionDevice *sd;
 780
 781         assert(s);
 782
 783         if (!s->user)
 784                 return -ESTALE;
 785
 786         if (s->started)
 787                 log_struct(s->class == SESSION_BACKGROUND ? LOG_DEBUG : LOG_INFO,
 788                            "MESSAGE_ID=" SD_MESSAGE_SESSION_STOP_STR,
 789                            "SESSION_ID=%s", s->id,
 790                            "USER_ID=%s", s->user->name,
 791                            "LEADER="PID_FMT, s->leader,
 792                            LOG_MESSAGE("Removed session %s.", s->id),
 793                            NULL);
 794
 795         s->timer_event_source = sd_event_source_unref(s->timer_event_source);
 796
 797         if (s->seat)
 798                 seat_evict_position(s->seat, s);
 799
 800         /* Kill session devices */
 801         while ((sd = hashmap_first(s->devices)))
 802                 session_device_free(sd);
 803
 804         (void) unlink(s->state_file);
 805         session_add_to_gc_queue(s);
 806         user_add_to_gc_queue(s->user);
 807
 808         if (s->started) {
 809                 session_send_signal(s, false);
 810                 s->started = false;
 811         }
 812
 813         if (s->seat) {
 814                 if (s->seat->active == s)
 815                         seat_set_active(s->seat, NULL);
 816
 817                 seat_save(s->seat);
 818         }
 819
 820         user_save(s->user);
 821         user_send_changed(s->user, "Display", NULL);
 822
 823         return 0;
 824 }
 825
 826 static int release_timeout_callback(sd_event_source *es, uint64_t usec, void *userdata) {
 827         Session *s = userdata;
 828
 829         assert(es);
 830         assert(s);
 831
 832         session_stop(s, false);
 833         return 0;
 834 }
 835
 836 int session_release(Session *s) {
 837         assert(s);
 838
 839         if (!s->started || s->stopping)
 840                 return 0;
 841
 842         if (s->timer_event_source)
 843                 return 0;
 844
 845         return sd_event_add_time(s->manager->event,
 846                                  &s->timer_event_source,
 847                                  CLOCK_MONOTONIC,
 848                                  now(CLOCK_MONOTONIC) + RELEASE_USEC, 0,
 849                                  release_timeout_callback, s);
 850 }
 851
 852 bool session_is_active(Session *s) {
 853         assert(s);
 854
 855         if (!s->seat)
 856                 return true;
 857
 858         return s->seat->active == s;
 859 }
 860
 861 static int get_tty_atime(const char *tty, usec_t *atime) {
 862         _cleanup_free_ char *p = NULL;
 863         struct stat st;
 864
 865         assert(tty);
 866         assert(atime);
 867
 868         if (!path_is_absolute(tty)) {
 869                 p = strappend("/dev/", tty);
 870                 if (!p)
 871                         return -ENOMEM;
 872
 873                 tty = p;
 874         } else if (!path_startswith(tty, "/dev/"))
 875                 return -ENOENT;
 876
 877         if (lstat(tty, &st) < 0)
 878                 return -errno;
 879
 880         *atime = timespec_load(&st.st_atim);
 881         return 0;
 882 }
 883
 884 static int get_process_ctty_atime(pid_t pid, usec_t *atime) {
 885         _cleanup_free_ char *p = NULL;
 886         int r;
 887
 888         assert(pid > 0);
 889         assert(atime);
 890
 891         r = get_ctty(pid, NULL, &p);
 892         if (r < 0)
 893                 return r;
 894
 895         return get_tty_atime(p, atime);
 896 }
 897
 898 int session_get_idle_hint(Session *s, dual_timestamp *t) {
 899         usec_t atime = 0, n;
 900         int r;
 901
 902         assert(s);
 903
 904         /* Explicit idle hint is set */
 905         if (s->idle_hint) {
 906                 if (t)
 907                         *t = s->idle_hint_timestamp;
 908
 909                 return s->idle_hint;
 910         }
 911
 912         /* Graphical sessions should really implement a real
 913          * idle hint logic */
 914         if (SESSION_TYPE_IS_GRAPHICAL(s->type))
 915                 goto dont_know;
 916
 917         /* For sessions with an explicitly configured tty, let's check
 918          * its atime */
 919         if (s->tty) {
 920                 r = get_tty_atime(s->tty, &atime);
 921                 if (r >= 0)
 922                         goto found_atime;
 923         }
 924
 925         /* For sessions with a leader but no explicitly configured
 926          * tty, let's check the controlling tty of the leader */
 927         if (s->leader > 0) {
 928                 r = get_process_ctty_atime(s->leader, &atime);
 929                 if (r >= 0)
 930                         goto found_atime;
 931         }
 932
 933 dont_know:
 934         if (t)
 935                 *t = s->idle_hint_timestamp;
 936
 937         return 0;
 938
 939 found_atime:
 940         if (t)
 941                 dual_timestamp_from_realtime(t, atime);
 942
 943         n = now(CLOCK_REALTIME);
 944
 945         if (s->manager->idle_action_usec <= 0)
 946                 return 0;
 947
 948         return atime + s->manager->idle_action_usec <= n;
 949 }
 950
 951 void session_set_idle_hint(Session *s, bool b) {
 952         assert(s);
 953
 954         if (s->idle_hint == b)
 955                 return;
 956
 957         s->idle_hint = b;
 958         dual_timestamp_get(&s->idle_hint_timestamp);
 959
 960         session_send_changed(s, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 961
 962         if (s->seat)
 963                 seat_send_changed(s->seat, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 964
 965         user_send_changed(s->user, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 966         manager_send_changed(s->manager, "IdleHint", "IdleSinceHint", "IdleSinceHintMonotonic", NULL);
 967 }
 968
 969 int session_get_locked_hint(Session *s) {
 970         assert(s);
 971
 972         return s->locked_hint;
 973 }
 974
 975 void session_set_locked_hint(Session *s, bool b) {
 976         assert(s);
 977
 978         if (s->locked_hint == b)
 979                 return;
 980
 981         s->locked_hint = b;
 982
 983         session_send_changed(s, "LockedHint", NULL);
 984 }
 985
 986 static int session_dispatch_fifo(sd_event_source *es, int fd, uint32_t revents, void *userdata) {
 987         Session *s = userdata;
 988
 989         assert(s);
 990         assert(s->fifo_fd == fd);
 991
 992         /* EOF on the FIFO means the session died abnormally. */
 993
 994         session_remove_fifo(s);
 995         session_stop(s, false);
 996
 997         return 1;
 998 }
 999
1000 int session_create_fifo(Session *s) {
1001         int r;
1002
1003         assert(s);
1004
1005         /* Create FIFO */
1006         if (!s->fifo_path) {
1007                 r = mkdir_safe_label("/run/systemd/sessions", 0755, 0, 0);
1008                 if (r < 0)
1009                         return r;
1010
1011                 if (asprintf(&s->fifo_path, "/run/systemd/sessions/%s.ref", s->id) < 0)
1012                         return -ENOMEM;
1013
1014                 if (mkfifo(s->fifo_path, 0600) < 0 && errno != EEXIST)
1015                         return -errno;
1016         }
1017
1018         /* Open reading side */
1019         if (s->fifo_fd < 0) {
1020                 s->fifo_fd = open(s->fifo_path, O_RDONLY|O_CLOEXEC|O_NDELAY);
1021                 if (s->fifo_fd < 0)
1022                         return -errno;
1023
1024         }
1025
1026         if (!s->fifo_event_source) {
1027                 r = sd_event_add_io(s->manager->event, &s->fifo_event_source, s->fifo_fd, 0, session_dispatch_fifo, s);
1028                 if (r < 0)
1029                         return r;
1030
1031                 /* Let's make sure we noticed dead sessions before we process new bus requests (which might create new
1032                  * sessions). */
1033                 r = sd_event_source_set_priority(s->fifo_event_source, SD_EVENT_PRIORITY_NORMAL-10);
1034                 if (r < 0)
1035                         return r;
1036         }
1037
1038         /* Open writing side */
1039         r = open(s->fifo_path, O_WRONLY|O_CLOEXEC|O_NDELAY);
1040         if (r < 0)
1041                 return -errno;
1042
1043         return r;
1044 }
1045
1046 static void session_remove_fifo(Session *s) {
1047         assert(s);
1048
1049         s->fifo_event_source = sd_event_source_unref(s->fifo_event_source);
1050         s->fifo_fd = safe_close(s->fifo_fd);
1051
1052         if (s->fifo_path) {
1053                 unlink(s->fifo_path);
1054                 s->fifo_path = mfree(s->fifo_path);
1055         }
1056 }
1057
1058 bool session_check_gc(Session *s, bool drop_not_started) {
1059         assert(s);
1060
1061         if (drop_not_started && !s->started)
1062                 return false;
1063
1064         if (!s->user)
1065                 return false;
1066
1067         if (s->fifo_fd >= 0) {
1068                 if (pipe_eof(s->fifo_fd) <= 0)
1069                         return true;
1070         }
1071
1072 #if 0 /// elogind supports neither scopes nor jobs
1073         if (s->scope_job && manager_job_is_active(s->manager, s->scope_job))
1074                 return true;
1075
1076         if (s->scope && manager_unit_is_active(s->manager, s->scope))
1077                 return true;
1078 #endif // 0
1079
1080         return false;
1081 }
1082
1083 void session_add_to_gc_queue(Session *s) {
1084         assert(s);
1085
1086         if (s->in_gc_queue)
1087                 return;
1088
1089         LIST_PREPEND(gc_queue, s->manager->session_gc_queue, s);
1090         s->in_gc_queue = true;
1091 }
1092
1093 SessionState session_get_state(Session *s) {
1094         assert(s);
1095
1096         /* always check closing first */
1097         if (s->stopping || s->timer_event_source)
1098                 return SESSION_CLOSING;
1099
1100 #if 0 /// elogind does not support systemd scope_jobs
1101         if (s->scope_job || s->fifo_fd < 0)
1102 #else
1103         if (s->fifo_fd < 0)
1104 #endif // 0
1105                 return SESSION_OPENING;
1106
1107         if (session_is_active(s))
1108                 return SESSION_ACTIVE;
1109
1110         return SESSION_ONLINE;
1111 }
1112
1113 int session_kill(Session *s, KillWho who, int signo) {
1114         assert(s);
1115
1116 #if 0 /// Without direct cgroup support, elogind can not kill sessions
1117         if (!s->scope)
1118                 return -ESRCH;
1119
1120         return manager_kill_unit(s->manager, s->scope, who, signo, NULL);
1121 #else
1122         if (who == KILL_LEADER) {
1123                 if (s->leader <= 0)
1124                         return -ESRCH;
1125
1126                 /* FIXME: verify that leader is in cgroup?  */
1127
1128                 if (kill(s->leader, signo) < 0) {
1129                         return log_error_errno(errno, "Failed to kill process leader %d for session %s: %m", s->leader, s->id);
1130                 }
1131                 return 0;
1132         } else
1133                 return cg_kill_recursive (SYSTEMD_CGROUP_CONTROLLER, s->id, signo,
1134                                           CGROUP_IGNORE_SELF | CGROUP_REMOVE,
1135                                           NULL, NULL, NULL);
1136 #endif // 0
1137 }
1138
1139 static int session_open_vt(Session *s) {
1140         char path[sizeof("/dev/tty") + DECIMAL_STR_MAX(s->vtnr)];
1141
1142         if (s->vtnr < 1)
1143                 return -ENODEV;
1144
1145         if (s->vtfd >= 0)
1146                 return s->vtfd;
1147
1148         sprintf(path, "/dev/tty%u", s->vtnr);
1149         s->vtfd = open_terminal(path, O_RDWR | O_CLOEXEC | O_NONBLOCK | O_NOCTTY);
1150         if (s->vtfd < 0)
1151                 return log_error_errno(s->vtfd, "cannot open VT %s of session %s: %m", path, s->id);
1152
1153         return s->vtfd;
1154 }
1155
1156 int session_prepare_vt(Session *s) {
1157         int vt, r;
1158         struct vt_mode mode = { 0 };
1159
1160         if (s->vtnr < 1)
1161                 return 0;
1162
1163         vt = session_open_vt(s);
1164         if (vt < 0)
1165                 return vt;
1166
1167         r = fchown(vt, s->user->uid, -1);
1168         if (r < 0) {
1169                 r = log_error_errno(errno,
1170                                     "Cannot change owner of /dev/tty%u: %m",
1171                                     s->vtnr);
1172                 goto error;
1173         }
1174
1175         r = ioctl(vt, KDSKBMODE, K_OFF);
1176         if (r < 0) {
1177                 r = log_error_errno(errno,
1178                                     "Cannot set K_OFF on /dev/tty%u: %m",
1179                                     s->vtnr);
1180                 goto error;
1181         }
1182
1183         r = ioctl(vt, KDSETMODE, KD_GRAPHICS);
1184         if (r < 0) {
1185                 r = log_error_errno(errno,
1186                                     "Cannot set KD_GRAPHICS on /dev/tty%u: %m",
1187                                     s->vtnr);
1188                 goto error;
1189         }
1190
1191         /* Oh, thanks to the VT layer, VT_AUTO does not work with KD_GRAPHICS.
1192          * So we need a dummy handler here which just acknowledges *all* VT
1193          * switch requests. */
1194         mode.mode = VT_PROCESS;
1195         mode.relsig = SIGRTMIN;
1196         mode.acqsig = SIGRTMIN + 1;
1197         r = ioctl(vt, VT_SETMODE, &mode);
1198         if (r < 0) {
1199                 r = log_error_errno(errno,
1200                                     "Cannot set VT_PROCESS on /dev/tty%u: %m",
1201                                     s->vtnr);
1202                 goto error;
1203         }
1204
1205         return 0;
1206
1207 error:
1208         session_restore_vt(s);
1209         return r;
1210 }
1211
1212 void session_restore_vt(Session *s) {
1213
1214         static const struct vt_mode mode = {
1215                 .mode = VT_AUTO,
1216         };
1217
1218         _cleanup_free_ char *utf8 = NULL;
1219         int vt, kb, old_fd;
1220
1221         /* We need to get a fresh handle to the virtual terminal,
1222          * since the old file-descriptor is potentially in a hung-up
1223          * state after the controlling process exited; we do a
1224          * little dance to avoid having the terminal be available
1225          * for reuse before we've cleaned it up.
1226          */
1227         old_fd = s->vtfd;
1228         s->vtfd = -1;
1229
1230         vt = session_open_vt(s);
1231         safe_close(old_fd);
1232
1233         if (vt < 0)
1234                 return;
1235
1236         (void) ioctl(vt, KDSETMODE, KD_TEXT);
1237
1238         if (read_one_line_file("/sys/module/vt/parameters/default_utf8", &utf8) >= 0 && *utf8 == '1')
1239                 kb = K_UNICODE;
1240         else
1241                 kb = K_XLATE;
1242
1243         (void) ioctl(vt, KDSKBMODE, kb);
1244
1245         (void) ioctl(vt, VT_SETMODE, &mode);
1246         (void) fchown(vt, 0, (gid_t) -1);
1247
1248         s->vtfd = safe_close(s->vtfd);
1249 }
1250
1251 void session_leave_vt(Session *s) {
1252         int r;
1253
1254         assert(s);
1255
1256         /* This is called whenever we get a VT-switch signal from the kernel.
1257          * We acknowledge all of them unconditionally. Note that session are
1258          * free to overwrite those handlers and we only register them for
1259          * sessions with controllers. Legacy sessions are not affected.
1260          * However, if we switch from a non-legacy to a legacy session, we must
1261          * make sure to pause all device before acknowledging the switch. We
1262          * process the real switch only after we are notified via sysfs, so the
1263          * legacy session might have already started using the devices. If we
1264          * don't pause the devices before the switch, we might confuse the
1265          * session we switch to. */
1266
1267         if (s->vtfd < 0)
1268                 return;
1269
1270         session_device_pause_all(s);
1271         r = ioctl(s->vtfd, VT_RELDISP, 1);
1272         if (r < 0)
1273                 log_debug_errno(errno, "Cannot release VT of session %s: %m", s->id);
1274 }
1275
1276 bool session_is_controller(Session *s, const char *sender) {
1277         assert(s);
1278
1279         return streq_ptr(s->controller, sender);
1280 }
1281
1282 static void session_release_controller(Session *s, bool notify) {
1283         _cleanup_free_ char *name = NULL;
1284         SessionDevice *sd;
1285
1286         if (!s->controller)
1287                 return;
1288
1289         name = s->controller;
1290
1291         /* By resetting the controller before releasing the devices, we won't
1292          * send notification signals. This avoids sending useless notifications
1293          * if the controller is released on disconnects. */
1294         if (!notify)
1295                 s->controller = NULL;
1296
1297         while ((sd = hashmap_first(s->devices)))
1298                 session_device_free(sd);
1299
1300         s->controller = NULL;
1301         s->track = sd_bus_track_unref(s->track);
1302 }
1303
1304 static int on_bus_track(sd_bus_track *track, void *userdata) {
1305         Session *s = userdata;
1306
1307         assert(track);
1308         assert(s);
1309
1310         session_drop_controller(s);
1311
1312         return 0;
1313 }
1314
1315 int session_set_controller(Session *s, const char *sender, bool force, bool prepare) {
1316         _cleanup_free_ char *name = NULL;
1317         int r;
1318
1319         assert(s);
1320         assert(sender);
1321
1322         if (session_is_controller(s, sender))
1323                 return 0;
1324         if (s->controller && !force)
1325                 return -EBUSY;
1326
1327         name = strdup(sender);
1328         if (!name)
1329                 return -ENOMEM;
1330
1331         s->track = sd_bus_track_unref(s->track);
1332         r = sd_bus_track_new(s->manager->bus, &s->track, on_bus_track, s);
1333         if (r < 0)
1334                 return r;
1335
1336         r = sd_bus_track_add_name(s->track, name);
1337         if (r < 0)
1338                 return r;
1339
1340         /* When setting a session controller, we forcibly mute the VT and set
1341          * it into graphics-mode. Applications can override that by changing
1342          * VT state after calling TakeControl(). However, this serves as a good
1343          * default and well-behaving controllers can now ignore VTs entirely.
1344          * Note that we reset the VT on ReleaseControl() and if the controller
1345          * exits.
1346          * If logind crashes/restarts, we restore the controller during restart
1347          * (without preparing the VT since the controller has probably overridden
1348          * VT state by now) or reset the VT in case it crashed/exited, too. */
1349         if (prepare) {
1350                 r = session_prepare_vt(s);
1351                 if (r < 0) {
1352                         s->track = sd_bus_track_unref(s->track);
1353                         return r;
1354                 }
1355         }
1356
1357         session_release_controller(s, true);
1358         s->controller = name;
1359         name = NULL;
1360         session_save(s);
1361
1362         return 0;
1363 }
1364
1365 void session_drop_controller(Session *s) {
1366         assert(s);
1367
1368         if (!s->controller)
1369                 return;
1370
1371         s->track = sd_bus_track_unref(s->track);
1372         session_release_controller(s, false);
1373         session_save(s);
1374         session_restore_vt(s);
1375 }
1376
1377 static const char* const session_state_table[_SESSION_STATE_MAX] = {
1378         [SESSION_OPENING] = "opening",
1379         [SESSION_ONLINE] = "online",
1380         [SESSION_ACTIVE] = "active",
1381         [SESSION_CLOSING] = "closing"
1382 };
1383
1384 DEFINE_STRING_TABLE_LOOKUP(session_state, SessionState);
1385
1386 static const char* const session_type_table[_SESSION_TYPE_MAX] = {
1387         [SESSION_UNSPECIFIED] = "unspecified",
1388         [SESSION_TTY] = "tty",
1389         [SESSION_X11] = "x11",
1390         [SESSION_WAYLAND] = "wayland",
1391         [SESSION_MIR] = "mir",
1392         [SESSION_WEB] = "web",
1393 };
1394
1395 DEFINE_STRING_TABLE_LOOKUP(session_type, SessionType);
1396
1397 static const char* const session_class_table[_SESSION_CLASS_MAX] = {
1398         [SESSION_USER] = "user",
1399         [SESSION_GREETER] = "greeter",
1400         [SESSION_LOCK_SCREEN] = "lock-screen",
1401         [SESSION_BACKGROUND] = "background"
1402 };
1403
1404 DEFINE_STRING_TABLE_LOOKUP(session_class, SessionClass);
1405
1406 static const char* const kill_who_table[_KILL_WHO_MAX] = {
1407         [KILL_LEADER] = "leader",
1408         [KILL_ALL] = "all"
1409 };
1410
1411 DEFINE_STRING_TABLE_LOOKUP(kill_who, KillWho);